Bevy for non-Bevy users

## Goal Description

Bevy has a number of useful crates (`bevy_color`, `bevy_reflect`, `bevy_platform`, `bevy_math`...) that are fundamentally useful outside of "Bevy as a game engine". Others (such as `variadics_please` and `atomicow`) have been split out completely, while living in the Bevy organization. However, some combination of branding, awareness, communication and policy has hampered their broader adoption. We should define, implement and publicize a strategy for these standalone-compatible parts of Bevy to give back to the broader Rust community more effectively.

## Goal Status

This is a potential [Bevy Project Goal](https://bevy.org/learn/contribute/project-information/project-goals/). Its state on the [Project Goals Board](https://github.com/orgs/bevyengine/projects/23/views/1) determines if it is Proposed, Postponed, Blocked (Approved), Inactive (Approved), Active (Approved), Completed, or Declined.

- **Staffing SMEs**: Not yet staffed
- **Working Group Link**: Working Group not yet formed
- **Design Documents**: Design documents not yet written

Start by reviewing the Project Goals Board and the project-goals information linked in the issue, then inspect the listed crates: bevy_color, bevy_reflect, bevy_platform, bevy_math, variadics_please, and atomicow. The work is not yet scoped: design documents and a working group must be established before a strategy can be defined, implemented, and publicized.

Written by the indexing model from the issue text.